Facebook has thrown down the gauntlet in front of Google, introducing an online ad platform designed to help businesses reach its social network of 50 million users. With industry pundits predicting that Facebook would usher in a new era of socially-networked advertising, the Palo Alto, Calif., company introduced Facebook Ads, an ad system to help businesses target advertising to audiences they want through friends' referrals.

Facebook Ads, announced by CEO Mark Zuckerberg at an event in New York on Nov. 6, also includes an ad system that spreads brand messages virally through Facebook Social Ads and an interface that can be used by marketers to gauge relevant user activities on the site. Zuckerberg introduced Facebook Ads with the support of key partners, including Blockbuster, CBS, JPMorgan Chase, The Coca-Cola Company, Microsoft, Sony Pictures Television and Verizon Wireless.